Ratio between the number of star-forming (SFR > 0.02 M_⊙ yr⁻¹) and quiescent galaxies as a function of the distance to the nearest neighbour d_n. Results are shown at low redshift for low-mass (solid line) and massive galaxies (dashed line). In black, we show the ratio of the field galaxies (galaxies in the isolated regions between 6 R₅₀₀ and 7 R₅₀₀ of each cluster) and in red the ratio of galaxies in the inner cluster regions (0.25 R₅₀₀ < r < 0.5 R₅₀₀). Narrow radial bins are selected to disentangle the local density effects from radial dependence; their importance is demonstrated with a blue solid plot, depicting low-mass population in a wider radial bin (0 < r < R₅₀₀). BCGs are excluded in all plots. The coloured bands represent the 68% confidence intervals obtained with Poisson statistics (see Sect. 3).